Conventionally, a large amount of heat energy is released and lost as, for example, waste heat, light, etc. in various energy-using devices such as internal combustion engines including an automobile engine; heat exchangers including a boiler and air-conditioning equipment; motor generators including a power generator and a motor; and luminous devices including lightings.
Nowadays, recovery and recycling of released heat energy as an energy source has been required in view of energy conservation, and as such a method, a thermoelectric generation in which a pyroelectric element is used is known.
To be specific, for example, Patent Document 1 below has proposed a method using a power-generating apparatus including a rotating body, a plurality of pyroelectric elements attached to the outer peripheral surface of the rotating body, and a heating tub and a cooling tub that increase and decrease the temperature of the pyroelectric element based on the rotational driving of the rotating body; and by increasing and decreasing the temperature of the pyroelectric elements by the heat source and cooling source periodically, direct-current power or alternating-current power is taken out from the pyroelectric element.